Lassa Virus Seroprevalence in Sibirilia Commune, Bougouni District, Southern Mali

Abstract

Lassa virus (LASV) is endemic to several nations in West Africa. In Mali, LASV was unknown until an exported case of Lassa fever was reported in 2009. Since that time, rodent surveys have found evidence of LASV-infected Mastomys natalensis rats in several communities in southern Mali, near the border with Côte d'Ivoire. Despite increased awareness, to date only a single case of Lassa fever has been confirmed in Mali. We conducted a survey to determine the prevalence of LASV exposure among persons in 3 villages in southern Mali where the presence of infected rodents has been documented. LASV IgG seroprevalence ranged from 14.5% to 44% per village. No sex bias was noted; however, seropositivity rates increased with participant age. These findings confirm human LASV exposure in Mali and suggest that LASV infection/Lassa fever is a potential public health concern in southern Mali.

Keywords: Lassa fever; Lassa virus seroprevalence; West Africa; arenavirus; emerging infectious diseases; southern Mali; viral hemorrhagic fever; viruses; zoonoses.

Figure 1

Study sites for assessment of Lassa virus seroprevalence in humans, southern Mali, 2015. The 3 villages of Soromba, Banzana, and Bamba (within red square) in Sibirilia commune, Bougouni district, were selected on the basis of previous identification of Lassa virus–infected rodents in peridomestic settings.

Figure 2

Demographic characteristics of study population in assessment of Lassa virus seroprevalence, southern Mali, 2015. A) Age; B) sex.